traceable1 (thhamlin@gmail.com) writes:
> So, is the groupid = data_space_id?

The relation of sys.data_spaces, sys.destination_data_spaces and
sys.filegroups is a bit complicated. A filegroup is a data space,
but the opposite does not apply.

> Then is the data_space_id = partition_number? I'm still having
> trouble getting from allocation_units to partitions.

No, the data_space_id is not the partition number. Instead you join
sys.allocation_units to sys.partitions over the container_id,
and to make it even more complicated, you join to different columns
in sys.partitions depending on type of allocation unit. In sys.partitions
you find the partition number.

I'm sorry that I don't simply give you a query, but I don't have any
multiple-filegroup database set up, so I can't test.

--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se

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